21424012 has 12 divisors (see below), whose sum is σ = 39697560. Its totient is φ = 10081856.

The previous prime is 21424003. The next prime is 21424027. The reversal of 21424012 is 21042412.

It is a super-2 number, since 2×21424012² = 917976580352288, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157462 + ... + 157597.

It is an arithmetic number, because the mean of its divisors is an integer number (3308130).

Almost surely, 2^21424012 is an apocalyptic number.

It is an amenable number.

21424012 is a deficient number, since it is larger than the sum of its proper divisors (18273548).

21424012 is a wasteful number, since it uses less digits than its factorization.

21424012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315080 (or 315078 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21424012 is about 4628.6079980919. The cubic root of 21424012 is about 277.7369110131.

Adding to 21424012 its reverse (21042412), we get a palindrome (42466424).

The spelling of 21424012 in words is "twenty-one million, four hundred twenty-four thousand, twelve".